The Vitamin A-fat loading test is used to study chylomicron and chylomicron remnant clearance. This test was performed on subjects undergoing HDL turnover studies (see "Regulation of HDL levels by Genetic and Environmental Factors") to correlate postprandial lipoprotein HDL metabolic parameters. Also performed on subjects to study diet effects on Lp (a) levels (see "Role of Lp(a) in atherosclerosis").